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Non Facing Plaster Bricks

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Plasterer’s Guide to Using Non Facing Plaster Bricks in South Africa

Introduction

Plasterers across South Africa work with a wide range of wall substrates, but Non Facing Plaster Bricks (NFP) are among the most common on residential and commercial projects. These lower-cost bricks are designed to be plastered over, not left exposed, which has major implications for how a plasterer prepares, prices, and executes a job. According to the Clay Brick Association of Southern Africa, NFP bricks are “intended for general building work which is to be plastered” and are not selected for colour or uniformity of appearance, unlike face bricks (Clay Brick Association – brick product types).

The problem many homeowners and even some contractors face is understanding how the choice of NFP bricks affects plaster thickness, finish quality, cracking risk, and overall cost. This article explains what a plasterer needs to know when working with NFP walls: how NFP differs from other brick types, how SANS standards and local practice apply, what realistic 2025/2026 costs look like in key provinces, and when to call a professional instead of attempting DIY plastering. Practical South African examples, checklists, and FAQs are included to help you make informed decisions on site.

Understanding Non Facing Plaster Bricks in the SA Context

What Are Non Facing Plaster Bricks?

Non Facing Plaster Bricks are masonry units that are structurally sound but not meant to be seen. They are specifically manufactured for walls that will be coated with plaster, paint, or other finishes.

According to the Clay Brick Association classification, NFP bricks fall into the “non-facing” category intended for plastered applications, while “face bricks” are selected or treated so that they can be left unplastered and exposed (Clay Brick Association – brick product types). NFP bricks may have:

  • Variable colour and texture
  • Minor surface imperfections
  • Slight dimensional variations within SANS tolerances

In concrete products, a similar distinction exists between concrete masonry units made for plastered walls and those with architectural finishes. AfriSam notes in its masonry guide that standard concrete blocks supplied for “general building purposes” are typically intended to be plastered, rather than left exposed (AfriSam – Masonry Handbook).

SANS Standards Relevant to NFP Bricks and Plastering

NFP bricks and the plaster applied to them are governed by several South African standards:

  • SANS 227 covers burnt clay masonry units, including loadbearing face and non-face bricks and blocks (SABS – SANS 227 listing).
  • SANS 1215 covers concrete masonry units for loadbearing applications, again distinguishing units for plastered vs exposed use (SABS – SANS 1215 listing).
  • SANS 2001-CM1 (Construction Works – Masonry Walling) provides requirements for workmanship and tolerances for masonry walls before finishing (SABS – SANS 2001-CM1 listing).
  • SANS 2001-CR3 (if a plaster system is part of a larger cladding/finishing specification) and related codes guide plastering and rendering practices.

These standards influence allowable tolerances for brickwork, bond patterns, mortar joints and, ultimately, how much correction a plasterer must perform on site.

How Non Facing Plaster Bricks Affect Plastering Work

Brickwork Tolerances and Plaster Thickness

Because Non Facing Plaster Bricks are not selected for appearance, the underlying brickwork is often less dimensionally perfect than face-brick walls. As a plasterer, this affects:

Quick Answer
NFP walls typically require thicker and more corrective plaster work than face-brick walls. When pricing or planning, allow for 10–20 mm plaster thickness and additional preparation time on uneven areas.

Moisture, Suction and Plaster Adhesion

NFP bricks can vary in absorption rate depending on whether they are clay or concrete units and how they were fired or cured. The Cement & Concrete SA plaster guide highlights that different background suctions (how quickly a substrate absorbs water) strongly influence the plaster’s workability, bond and tendency to crack or debond (Cement & Concrete SA – Plaster, Render & Screed).

For plasterers this means:

  • High-suction clay NFP walls should be lightly dampened before plastering to avoid rapid moisture loss from the plaster.
  • Low-suction concrete masonry or dense NFP bricks may need a key coat / spatterdash or bonding agent, as recommended in the CCSA guide.
  • Joints should be well filled and raked to provide a mechanical key for the plaster.

Pro Tip
On hot, dry Gauteng or inland sites, pre-wet NFP clay brickwork with a fine spray and allow surface water to disappear before plastering. This helps prevent premature drying and plastic shrinkage cracking.

Choosing Non Facing Plaster Bricks vs Other Masonry Options

Comparison: NFP Bricks vs Face Bricks vs Concrete Blocks

Feature / Criterion Non Facing Plaster Bricks (NFP) Face Bricks Concrete Blocks (Plaster Grade)
Primary purpose Structural, must be plastered Structural + aesthetic (exposed finish) Structural, normally plastered or rendered
Appearance selection Not selected for colour/texture Selected/treated for appearance Typically uniform grey; not for architectural exposed use
Typical unit price (2025 indicative)* Lower than face bricks Highest of the three Often competitive with, or cheaper than, NFP per m² of wall
Plaster requirement Yes, full coverage Usually none (tuckpointing only) Yes, full coverage
Work for plasterer More levelling and correction likely Usually minimal (internal plaster only if required) Similar to NFP; may need strong key coat on smooth units
Common SA use Houses, boundary walls, internal partitions Upmarket homes, complexes, feature walls Cost-effective external and internal walls in residential & commercial

*Prices vary significantly by region and supplier; see cost section below.

The Clay Brick Association notes that non-facing bricks are widely used for plastered internal and external walls, while face bricks are used where appearance is a key requirement and plaster is not intended (Clay Brick Association – brick product types).

Technical Considerations for Plasterers

When working on NFP walls:

  • Check joint quality – SANS 2001-CM1 tolerances for alignment and joint fullness should be met; hollow or poorly filled joints can cause plaster failure (SABS – SANS 2001-CM1 listing).
  • Control joints – On long external NFP walls, make sure movement joints are present or planned; these can be mirrored or reinforced in the plaster finish to manage cracking.
  • Corner beads and stops – Particularly important on rough NFP work to achieve straight arrises and consistent thickness.

Common Mistake
Skimming thin (5–7 mm) plaster directly onto very uneven NFP brickwork to “save on plaster” often leads to waves, hollow spots, and debonding. It usually costs more later to hack off and redo than to apply a properly levelled 10–20 mm coat first time.

Practical Plastering Workflow on NFP Brick Walls

Step-by-Step Approach for South African Sites

A typical plasterer’s workflow on a Non Facing Plaster Brick wall in South Africa is:

  1. Inspection and preparation
    • Check brick quality, joint filling and alignment.
    • Remove loose mortar, dust and efflorescence.
    • Dampen high-suction masonry (as per CCSA guidance on background preparation (Cement & Concrete SA – Plaster, Render & Screed)).
  2. Set out screeds (bands)
    • Establish vertical and horizontal screeds at corners and intervals to define finished plane and thickness.
  3. Mix selection
    • For most inland and coastal work, CCSA recommends plaster mixes in the 1:4 to 1:6 cement:sand range, with clean, well-graded plaster sand (Cement & Concrete SA – Plaster, Render & Screed).
    • In aggressive coastal environments, a slightly richer mix and correct cover to masonry are important.
  4. Application
    • Apply a first coat (often the full thickness on single-coat work).
    • Rule off to screeds and fill low spots (dubbing out).
    • Float to achieve required key (wood float for paint finish, steel trowel only at final stages if specified).
  5. Curing
    • Protect from direct sun and wind.
    • Lightly mist for at least 3 days, ideally up to 7, particularly in hot inland areas, as per CCSA curing recommendations (Cement & Concrete SA – Plaster, Render & Screed).

Example: Gauteng Residential Boundary Wall

Consider a 1.8 m high boundary wall in Johannesburg built with clay NFP bricks:

  • Brickwork is reasonably straight but with minor steps and irregularities.
  • Plaster thickness averages 15 mm to straighten the wall.
  • Plasterer allows extra time for:
    • Dubbing out larger hollows,
    • Installing corner beads on gate pillars,
    • Managing fast drying due to Highveld conditions.

In this case, the choice of NFP bricks keeps wall construction more affordable, but the plasterer must budget for additional material and labour to deliver a flat, crack-resistant finish.

Costs and Pricing (2025/2026) for Plastering NFP Brick Walls

Typical Plastering Rates per m²

Plastering prices in South Africa vary with region, access, thickness and finish quality. Collating indications from local building cost discussions and contractor listings on platforms like Snupit and Procompare, external and internal plastering to brickwork in 2024–2025 typically ranges from roughly R90–R180 per m² for labour only, and R150–R280 per m² including standard materials, in mainstream urban areas (e.g. examples of plastering quotes on Snupit – plastering services and Procompare – plastering contractors).

For NFP walls that are uneven or require thicker plaster, expect to be toward the upper end of these ranges.

Approximate 2025/2026 Regional Ranges (per m², NFP walls)

These are broad working ranges for standard-quality work on residential or light commercial projects:

  • Gauteng (Johannesburg/Pretoria)
    • Labour only: ± R100–R170/m²
    • Labour + materials: ± R160–R260/m²
  • Western Cape (Cape Town and surrounds)
    • Labour only: ± R110–R180/m²
    • Labour + materials: ± R170–R280/m²
  • KwaZulu-Natal (Durban/eThekwini)
    • Labour only: ± R90–R160/m²
    • Labour + materials: ± R150–R250/m²

These estimates align with price bands commonly reflected in contractor marketplaces (e.g. plastering rates shown on Snupit – plastering services) and general building cost discussions on South African property portals such as Private Property and Property24, which show similar ranges for wet trade finishes on new builds and renovations (Private Property – building cost guide).

Factors That Push Costs Up or Down

Key cost drivers that apply specifically to Non Facing Plaster Bricks:

  • Wall accuracy: Poorly laid NFP brickwork needing extensive levelling will cost more.
  • Plaster thickness: Increasing from 10 mm to 20 mm significantly increases material usage.
  • Height and access: Double-storey work or complicated scaffolding increases labour time.
  • Exposure conditions: Coastal or high-traffic areas might require higher-spec mixes or additional coats.
  • Finish type: Smooth, high-end internal finishes cost more than rougher, bagged or sponge-textured external finishes.

Key Takeaway
On a typical NFP brick house in a major metro, allow R160–R260/m² for a competent contractor to supply and apply standard cement plaster in 2025/2026, with more for high-end architectural finishes or problematic brickwork.

When to Call a Professional Plasterer vs DIY

Honest Assessment of DIY on NFP Walls

Small, low-risk areas such as a garden shed wall or short internal partition can sometimes be plastered successfully by a careful DIYer following guidance from resources like Cement & Concrete SA’s plaster handbook (Cement & Concrete SA – Plaster, Render & Screed). However, Non Facing Plaster Bricks often present:

  • Uneven surfaces that require experienced screeding and levelling.
  • High or low suction backgrounds that need correct pre-treatment.
  • Structural or boundary walls, where cracking and water ingress can be costly.

Call a professional plasterer when:

  • The wall is part of your main house, especially external envelope walls.
  • The wall surface is obviously out of plumb or uneven, requiring significant correction.
  • You are in a coastal or high rainfall area where water ingress is a concern.
  • You need a high-quality internal finish ready for painting with minimal sanding/filling.
  • The project height or access requires scaffolding or specialised safety measures.

A professional who understands SANS requirements and local conditions can help ensure that the plaster system is durable and compatible with the NFP bricks, reducing future maintenance and repainting costs.

Common Mistakes When Plastering Non Facing Plaster Bricks

Technical and Practical Errors to Avoid

  1. Ignoring substrate movement and control joints
    • Long NFP walls without control joints nearly always crack. Plasterers should coordinate joints with the brickwork layout and structural engineer’s details.
  2. Incorrect water addition and mix proportions
    • Over-wet mixes or inconsistent batching weaken plaster. The CCSA guide stresses correct cement:sand ratios and minimal water additions to achieve workable, not sloppy, mixes (Cement & Concrete SA – Plaster, Render & Screed).
  3. No curing in hot, windy conditions
    • Rapid moisture loss leads to shrinkage cracking and dusting surfaces. Regular light misting is essential, especially on sun-exposed NFP facades.
  4. Plastering over damp or salt-contaminated NFP brickwork
    • Rising damp or significant efflorescence should be addressed first. Simply plastering over these issues leads to blistering and peeling.
  5. Inadequate thickness over uneven brickwork
    • Trying to “stretch” a thin coat over bad NFP brickwork usually results in telegraphed joints and hollows.

Common Mistake
Skipping substrate inspection on NFP walls because “plaster will hide it” is risky. Structural cracks, damp, or loose masonry should be resolved before applying any plaster.

FAQs About Non Facing Plaster Bricks and Plastering

Q: What exactly are Non Facing Plaster Bricks and how are they different from normal bricks?

A: Non Facing Plaster Bricks are structural bricks manufactured for walls that will be plastered, not left exposed. They are not selected for consistent colour or surface appearance. The Clay Brick Association classifies them as “non-facing” units intended for general building work that will be plastered, compared with face bricks which are chosen for aesthetic qualities and can remain visible without plaster (Clay Brick Association – brick product types). Structurally they can perform similarly to face bricks, but visually they are rougher and less uniform.

Q: Do Non Facing Plaster Bricks require a special plaster mix?

A: Not usually a completely special mix, but the background type and exposure matter. According to Cement & Concrete SA, standard plaster mixes of 1:4 to 1:6 cement:sand are suitable for most clay or concrete masonry, provided the sand is well graded and clean (Cement & Concrete SA – Plaster, Render & Screed). High-suction NFP clay bricks may need pre-wetting, while dense concrete units may need a key coat or bonding agent. In coastal regions, slightly richer mixes and careful curing are recommended to improve durability.

Q: How thick should plaster be on NFP walls in South Africa?

A: For most NFP brick walls, 10–20 mm total plaster thickness is common. The Clay Brick Association’s plastering guide notes that a minimum of 10 mm is generally recommended, with thicker coats needed to correct uneven brickwork or to achieve a very flat finish (Clay Brick Association – Plastering of Clay Masonry). External walls or highly irregular NFP backgrounds may require towards the upper end of this range, especially where walls must be straightened.

Q: What does it cost to plaster NFP brick walls in 2025/2026?

A: Prices vary by region and complexity, but typical South African rates for standard plastering to brickwork in urban areas fall in the range of R90–R180/m² (labour only) and R150–R280/m² (labour + materials) based on quotes and listings from local contractors on platforms like Snupit and Procompare (Snupit – plastering services, Procompare – plastering contractors). NFP walls that are very uneven or require thicker coats will be towards the higher end of these bands, particularly in Western Cape and Gauteng metros.

Q: Are Non Facing Plaster Bricks compliant with South African building standards?

A: Yes, provided they meet relevant SANS specifications. Clay NFP bricks should comply with SANS 227 for burnt clay masonry units, while concrete NFP blocks fall under SANS 1215 for concrete masonry units (SABS – SANS 227 listing, SABS – SANS 1215 listing). Walls built from these products and plastered in line with SANS 2001 requirements are acceptable for structural use, subject to design by a competent professional where required by building regulations.

Q: Can I leave Non Facing Plaster Bricks unplastered if I like the “raw” look?

A: It is technically possible, but not recommended. NFP bricks are not selected for consistent colour or surface quality and may weather poorly if exposed. The Clay Brick Association emphasises that non-facing bricks are intended for plastered applications, unlike face bricks which are produced to be left visible (Clay Brick Association – brick product types). Leaving NFP walls bare can lead to uneven staining, increased moisture ingress and maintenance issues.

Q: How do I minimise cracking when plastering NFP walls?

A: To reduce cracking, follow good practice: ensure brick joints are properly filled and walls are stable before plastering, pre-wet high-suction NFP bricks, use the correct cement:sand ratio, avoid overly wet mixes, apply a consistent thickness (10–20 mm) and cure the plaster by keeping it damp for several days. Cement & Concrete SA stresses proper curing and control of drying rates as key defence against shrinkage cracking (Cement & Concrete SA – Plaster, Render & Screed). Movement joints in long walls should also be respected and detailed in the plaster.

Conclusion

  • Non Facing Plaster Bricks are cost-effective structural units designed to be fully plastered, not left exposed.
  • NFP walls typically need 10–20 mm plaster thickness and more levelling than face-brick work, which directly affects labour and material costs.
  • Compliance with SANS 227, SANS 1215 and SANS 2001 standards, plus best-practice guidance from bodies like Cement & Concrete SA and the Clay Brick Association, helps ensure durable, crack-resistant finishes.
  • For most external and main internal walls, especially in coastal or high-value areas, using a professional plasterer is the safest option to protect your investment.

For professional plastering services in your area, contact our experienced team for a free consultation and quote on the best way to finish your walls built with Non Facing Plaster Bricks.

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